Every spring I check and air-up all the tires. I have the stock 9.00x20 NDTs, so 50 PSI in the rear, I now run 60 PSI in the front, and then max out the spare at 65 PSI. I change my oil and filters in the spring on the even numbered years. I'll probably incorporate changing the coolant filter at the same time now that I have one.
I then drain the air tanks every-day after driving it.
That's the only scheduled maintenance I've got for the truck. I do, however, do the pre-trip walk around checking brake fluid level, checking for other leaks, ensuring cargo cover is secured and I haven't left any tools sitting on the truck, and etc. I should incorporate checking the oil and coolant level as part of my pre-trip, but I get lazy as I only see a few drops here and there (I realize that doesn't mean something ELSE isn't going wrong...).
This past year I did drain and replace the gear oil in all 3 differentials, transmission, and transfer case, repack all bearings, replace all seals, new front boots, and rebuilt all wheel (brake) cylinders and adjust the brakes. At my usage I'll have to see how frequent of an endeavor that turns out to be. I think next time I'm going to get an electric pump to re-fill the differentials, transmission, and transfer case - that should make things far less awkward and difficult for me.
This is the 5th year I've owned my deuce and I've put ~1300 miles on it in total. I need to drive it more and I'm feeling a bit more confident after all that big service work has been done.